V1 Preamp Tube Simulator

Author: Kevin M  Date Posted:12 October 2026 

V1 Preamp Tube Analyzer

See how the V1 valve changes gain, headroom, volume and fizz
.CH1 V1 output.CH2 unclipped refClean
Gain 100Drive 5/10THD 0.0%
Clean headroom
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.
Saturation
--
.
Fizz & noise
--
.
Perceived volume
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.
Harmonic spectrum.Even (warm).Odd (edge)

Illustrative model of V1 behaviour, not a bench measurement of a specific amplifier.

1 · V1 tube typeGain factor
3 · Tone goal presets

Evatco tip: dropping gain from 100 to 50 does not halve your output volume. It mainly adds clean headroom and smooths saturation before the signal drives the power tubes.

12AX7 / ECC83 / B759

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How to Use the V1 Simulator

V1 is the first preamp tube your guitar signal hits, so it sets how much gain the rest of your amp has to work with. Use this tool to see how swapping V1 changes headroom, saturation and fizz before you buy a tube.

STEP 1

Pick a V1 tube

The number beside each tube is its gain, from 12AX7 (100) down to 12AU7 (~20).

STEP 2

Set your volume

Set Amp volume / drive to where you play: 1 (bedroom) to 10 (cranked).

STEP 3

Watch the waveform

The flatter CH1 gets compared to clean CH2, the more V1 is breaking up.

STEP 4

Try a tone goal

Tap a preset like Clean Headroom or Tame Gain Fizz for a suggested setup.

Reading the results

  • Clean headroom: how loud you can go before the tube starts to break up.
  • Saturation & THD: how much distortion the stage is adding.
  • Fizz & noise: harsh top-end hash. A lower-gain V1 usually reduces it.
  • Harmonic spectrum: even harmonics sound warm; odd harmonics add edge and bite.
  • Perceived volume: dropping V1 gain doesn't halve your volume. It mostly buys you headroom.

This is an illustrative model, not a measurement of your specific amp. Results will vary with circuit, power tubes and speakers.